pH-Responsive Oxygen and Hydrogen Peroxide Self-Supplying Nanosystem for Photodynamic and Chemodynamic Therapy of Wound Infection.

The combination of photodynamic therapy (PDT) and chemodynamic therapy (CDT) has been continuously explored in the antibacterial aspect and has achieved more effective antibacterial effect than a single therapy. We design a pH-responsive O2 and H2O2 self-supplying zeolitic imidazolate framework-67 (ZIF-67) nanosystem for PDT/CDT of wound infection. Under the acidic inflammatory conditions, ZIF-67 can degrade to produce Co2+ and release CaO2 and graphene quantum dots (GQDs). The exposed CaO2 reacted with water to generate H2O2 and O2. The self-supplied O2 alleviates hypoxia at the site of inflammation and enhances external light-initiated GQD-mediated PDT, while H2O2 was catalyzed by endogenous Co2+ to produce hydroxyl radicals for Co2+-triggered CDT. In vitro and in vivo experiments confirm that CaO2/GQDs@ZIF-67 has a combined PDT/CDT effect. The antibacterial mechanism indicates that bacteria post-treated with CaO2/GQDs@ZIF-67 may be sterilized by reactive oxygen species-mediated oxidative stress and the leakage of bacterial contents. The experiments also find that CaO2/GQDs@ZIF-67 may activate the immune response and enhance the therapeutic effect by activating the cyclic GMP-AMP synthase-stimulator of interferon genes signaling pathway.

Segmented scan modes and polarity-based LC-MS for pharmacokinetic interaction study between Fufang Danshen Dripping Pill and Clopidogrel Bisulfate Tablet.

Fufang Danshen Dripping Pill (FDDP) and Clopidogrel Bisulfate Tablet (CBT) are usually combined for treatment of coronary artery diseases in clinical. To investigate the pharmacokinetic interaction between FDDP and CBT after oral administration of FDDP, CBT and their combination in rats, a novel LC-MS method with segmented scan modes (multiple reaction monitoring and selected ion monitoring) and polarity (positive and negative ionization) was developed. Clopidogrel and the main active ingredients of FDDP, with different chemical and ionization properties, were simultaneously quantified in plasma in a single run. The method was validated in terms of specificity, linearity, precision, accuracy, recovery, matrix effect and stability. As a result, co-administration of FDDP and CBT significantly altered the pharmacokinetic parameters of danshensu, ginsenoside Rb1, dihydrotanshinone I, tanshinone I and tanshinone IIA of FDDP, as well as clopidogrel. Mechanism studies suggested that induction of liver cytochrome P450 isozymes CYP2C11 and CYP3A1 by co-administration, as well as inhibition of carboxyl esterase 1, was partly responsible for FDDP-CBT pharmacokinetic interactions. The developed LC-MS method could be used to simultaneously quantify different types of in vivo analytes in a single run, and the results could be used for clinical medication guidance of FDDP and CBT.

Pharmacokinetics of ginkgolides A, B and K after single and multiple intravenous infusions and their interactions with midazolam in healthy Chinese male subjects.

PURPOSE: Ginkgo terpene lactones meglumine injection (GMI) is a novel preparation of traditional Chinese medicine that contains ginkgolides A, B and K (GA, GB, GK, respectively) as its primary components. In this study we evaluated the safety, tolerability and pharmacokinetics of these three ginkgolides after single and multiple intravenous infusions of GMI. We also investigated the effect of GMI on cytochrome P450 3A4 (CYP3A4) in healthy Chinese volunteers. METHODS: In this open-label, placebo-controlled study 15 subjects were randomly assigned to receive GMI or matched placebo (4:1 ratio). All subjects first received midazolam (MDZ) on day 1, followed by a 6-day washout. On Day 8, the subjects were started on once-daily dosing of either GMI or placebo for 14 days. Lastly, on Day 22 the subjects were given second dose of MDZ + GMI or MDZ + placebo. Plasma concentrations of ginkgolides, MDZ and its metabolite 1-hydroxy midazolam were quantified. RESULTS: The steady-state conditions of GA, GB and GK were achieved after 6 days of daily dosing. Following a single dose of GMI (Day 8) the area under the concentration-timecurve from zero to 24 h after administration (AUC0-24h) of GA, GB and GK (arithmetic ± standard deviation) was 4.10 ± 1.06, 4.61 ± 1.31 and 0.127 ± 0.102 h µg/mL, respectively; the corresponding values following multiple doses of GMI (Day 19) were 3.94 ± 1.16, 5.00 ± 1.55 and 0.118 ± 0.096 h µg/mL, respectively. The mean accumulation ratios were 0.95, 1.08 and 0.89 for GA, GB and GK, respectively. Additionally, the geometric mean [peak concentration (Cmax) and AUC0-24h] ratios of MDZ and 1-hydroxy midazolam were all within the specified acceptance ranges in the MDZ + placebo treatment and MDZ + GMI treatment. CONCLUSIONS: Our results show that GMI was well tolerated during the entire study. There was no systemic accumulation and no significant effects on the pharmacokinetics of MDZ in healthy Chinese male subjects after repeated dosing of GMI.

Aptamer based fluorometric ß-lactoglobulin assay based on the use of magnetic nanoparticles and carbon dots.

The authors describe a fluorometric aptamer based assay for detecting ß-lactoglobulin by using carbon dots (C-dots) as a signal indicator. The aptamer was immoblized on magnetite (Fe3O4) nanoparticles (MNPs), and the C-dots served as a label for the complementary oligonucleotide (cDNA). The assay is based on the hybridization that takes place between aptamer and cDNA. In the presence of ß-lactoglobulin (ß-LG), the aptamer preferentially binds to ß-LG, and this leads to a partial release of the C-dots-cDNA into the solution. After magnetic separation, the supernatant of the solution contains the released C-dots-cDNA which are quantified by fluorometry, best under excitation/emission wavelengths of 354/447 nm. Under the optimal conditions, the fluorescence intensity is proportional to the logarithm of the ß-LG concentration in the 0.25 to 50 ng mL-1 range, with a 37 pg mL-1 detection limit. The method was successfully applied to the determination of ß-LG in hypoallergenic formulations, and the results demonstrated that this assay is a promising tool in food quality control. Conceivably, it also provides the opportunity for detection of other analytes. Graphical abstract Schematic of a novel aptamer based fluorometric ß-lactoglobulin assay based on the use of magnetite (Fe3O4) nanoparticles (MNPs) and carbon dots (C-dots). C-dots were used as a signal indicator and Fe3O4 MNPs acted as a magnetic separator. This assay exhibits high sensitivity and selectivity with a detection limit as low as 37 pg mL-1.